Nascent roots and stems
Displace freshly warming earth
Chill nights slow their birth
March in California is the envy of the East Coast. Still bundled against blizzards, they hear about our sunny days and emerging blooms as they look out at a sea of snow. But don’t be fooled by all the new plants breaking ground.
My last frost date is March 15th, but we’ve already reached temperatures as high as 80°F! To tender young shoots and first leaves (cotyledons), a sudden drop in temperature can be deadly. As tempting as it may be to trim away frost-damaged plant parts in early March, it is a good idea to wait until closer to the middle of the month, just to be on the safe side. Fret not, however, there are many tasks to keep you busy in the garden in March!
Citrus pruning should not be started until after March 15th, but now is the time to seriously inspect for mummies. Mummies are those shriveled up, fuzzy gray oranges that house millions of fungal spores. When removing mummies, try to disturb them as little as possible, or cover them with a plastic bag before removing them from the tree. If a citrus tree shows signs of chlorosis (yellowing) on older leaves, it may indicate a nitrogen deficiency. Interveinal (between leaf veins) chlorosis usually means a micronutrient, such as iron or manganese, is needed. Our soil tends to be very low on iron, but you can’t know for sure without a soil test. After the danger of frost has (nearly) completely passed, on March 15th, give citrus trees a good pruning. Just be sure to keep a lookout for bird nests. It’s that time of year!
Walking on wet ground causes soil compaction. This is especially true for areas with heavy clay soil. Rather than walking on wet soil, stay on paths, install stepping stones, or just wait for it to dry. Compacted soil is particularly difficult for young roots to move through, and it can cause drainage problems. Also, digging wet soil damages soil structure. The best treatment for compacted soil is a thick layer of free arborist wood chips. Amazing things happen under mulch!
Winter and spring moisture provide the perfect habitat for many pathogens. You can prevent diseases, such as fireblight on apples, pears, quince, and loquat, with fixed copper sprays. You can also reduce the chance of powdery mildew on grapes by applying sulfur at this time.
Feed young trees
As young trees continue putting out new roots, shoots, and leaves, they will benefit from being fed in March. Check the specific species of tree for more information on how much fertilizer should be provided. Since my soil tests indicate that everything is present in abundance, except for nitrogen and iron, those are the only two I add. Money saved. Environment protected. Check.
Another common March task is to inspect and repair sprinklers, drip systems, and water collection systems. How do you know if you have an irrigation leak? It can be difficult to spot, especially if it is small. The most common indication is an area that gets and stays wet or green longer than everywhere else. Sprinklers should be aimed so that they do not hit tree trunks, walkways, driveways, or sidewalks. The former can cause fungal diseases and the latter creates wasteful urban drool.
March is also a good time to prune out dead branches and twigs from fruit and nut trees and ornamental trees and shrubs. It is easier to see the structure of each plant before it is covered with leaves. The only exception is those trees susceptible to Eutypa dieback. Pruning grapes or stone fruits, such as apricot or cherry, before the rains are completely over can create an opportunity for infection. I know it's hard to wait, but you should.
Slugs and snails
Our warming temperatures and moisture work together to create the perfect habitat for slugs and snails. These mollusks can devastate seedlings in a single night, so be prepared. I urge you to follow the link to slugs and snails to learn more about the specific ingredients in different bait products. They are not created equally, and some can harm pets. Choose accordingly. Be on the lookout for pillbugs, too.
If you have not conducted a soil test recently, now is the time. Find out what is in your soil before you start adding plants or fertilizer.. This will help avoid nutrient imbalances that can wreak havoc on plant health.
Walk through your garden in March and you are sure to see weeds coming up in every location imaginable (and a few unimaginable places!). Your Number One March garden task is weeding. Since some weeds can go to seed in as little as a week, now is the time to cut them off at ground level with a hoe. Wait until later in the season and thousands of seeds will already be sown. Healthy weeds make great additions to the compost pile. Personally, I feed them to my chickens.
Enjoy the early blossoms!